1. Field of the Invention
This invention is concerned with refrigeration apparatus and in particular to means for improving the energy usage efficiency of a binary refrigerant refrigeration system utilizing a refrigerant flow circuit including heat exchangers in the below-freezing and above-freezing zones.
2. Description of the Background Art
In a paper presented before the International Refrigeration Congress in Moscow, Russia, in 1975, A. Lorenz and K. Meutzner describe a non-azeotropic two-component refrigerant domestic refrigerator-home freezer system. As shown in FIG. 4 of the publication, it was known, in 1975, to provide a refrigeration apparatus having a first evaporator in the freezer zone and a second evaporator in the above-freezing zone of a refrigerator, with a first heat exchanger between the condenser and the freezer evaporator, and a second heat exchanger between the freezer evaporator and the above-freezing compartment evaporator. The refrigerant comprised a binary refrigerant of R 22/R 11 composition.
Another binary refrigerant system is illustrated in U.S. Pat. No. 2,799,142 of Albert E. Schubert et al. for providing dual temperature levels of refrigeration in the system. The refrigerant components in the Schubert et al patent comprise Freon 22 and Freon 12. The system is arranged for selectively circulating one of the refrigerants, substantially purging the system of that refrigerant, and circulating the other refrigerant through the system, while purifying the first refrigerant during the circulation of the other refrigerant. The means for purifying the refrigerant comprises distilling means.